send_email

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden, and it does disclose the key behavioral trait: this is a demo that only records and does not actually send mail. That is genuinely useful. However, it omits whether sends are logged, whether recipients are validated, whether calls are rate-limited, or what the recorded result contains — for a side-effecting tool with zero annotation coverage this is a real gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One short sentence that front-loads the operation and appends the crucial demo caveat. Nothing is wasted, though the terseness is partly under-specification rather than pure efficiency.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and the demo caveat covers the most surprising behavior. Still, with three wholly undocumented required parameters and no annotations, the agent lacks enough information to construct a correct call in edge cases.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% across three required parameters, so the description needs to compensate and does not. It says nothing about expected format for 'to' (single address? comma-separated?), whether 'subject' may be empty, or whether 'body' supports HTML — all decisions an agent must make.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource ('Send an email'), which unambiguously identifies the operation. None of the sibling tools (purchase, publish, read_file, delete_resource) are email-related, so differentiation is implicit rather than needing explicit mention.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives, no prerequisites, and no mention of what happens with invalid addresses or unreachable recipients. The only usage-relevant note is that it is a demo that records rather than delivers, which speaks to behavior more than to selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.